Globalmente, o crescimento populacional gera uma maior demanda por energia, atualmente suprida por fontes fósseis. Nesse sentido, políticas públicas têm estimulado as fontes de energias renováveis, como por exemplo a produção de etanol de segunda geração (2G), a partir de materiais celulósicos, como a palha da cana-de-açúcar. Contudo, a remoção dessa palha pode alterar atributos químicos, físicos e biológicos do solo e, por fim, a produtividade da cultura. Portanto, o objetivo deste estudo é avaliar as mudanças ocasionadas pela remoção de quantidades de palha em atributos do solo e os impactos nos componentes de produção da cana-de-açúcar. O experimento foi conduzido próximo a cidade de Igaraçu do Tietê-SP. O solo do local foi classificado como Nitossolo Vermelho Eutróferrico Típico. O delineamento utilizado foi blocos ao acaso com cinco tratamentos e três repetições. Os tratamentos avaliados foram as seguintes quantidades de palha depositadas uniformemente na superfície do solo: 0; 2; 3,2 e 7,5 Mg ha-1 de massa de matéria seca; Adicionalmente, testou-se um tratamento com 7,5 Mg ha-1 de palha aleirada na entrelinha. Foram avaliados atributos químicos, físicos e biológicos do solo tais como, pH, macronutrientes, densidade e resistência à penetração, teor e estoques de carbono e nitrogênio e biomassa microbiana. Para a maioria dos atributos do solo, as camadas avaliadas foram: 0-10; 10-20; 20-30 cm, contudo, as camadas avaliadas para os atributos químicos, ao fim do ciclo, foram: 0-5; 5-10; 10-20; 20-30 cm. Em relação a planta, foram avaliados o número e altura de plantas, aos 7, 15, 30, 45, 60, 90, 180 e 390 dias após o corte (DAC). O índice de área foliar foi determinado aos 120, 150 e 180 DAC. A determinação da produtividade da cultura foi feita por biometria aos 390 DAC. Foi calculado o acúmulo de nutrientes na cultura para os tratamentos 0; 3,2; 7,5 Mg ha-1 ao fim do ciclo. Após um ano de implantação do experimento, as diferentes quantidades de palha não alteraram os atributos químicos, densidade do solo e o teor de estoques de C e N. Por outro lado, a deposição de 7,5 Mg ha-1 de palha reduziu a compactação do solo na entre linha de 150 cm. A deposição de maiores quantidades de palha interferiu na rebrota e perfilhamento inicial da cana-de-açúcar, contudo, com o decorrer do ciclo, as plantas se recuperaram, havendo uma estabilização similar no número e altura de planta entre os tratamentos, acarretando valores de IAF e produtividade similares. Dessa forma, conclui-se que para as condições encontradas neste estudo, a remoção da palha no curto prazo não provocou impactos negativos dos atributos químicos, físico e biológicos e, consequentemente redução na produtividade da cana-de-açúcar. Contudo, destaca-se a necessidade de monitorar os efeitos da remoção de palha de cana-de-açúcar nos atributos do solo e planta por médio e longo prazo, permitindo assim, um melhor entendimento acerca da sustentabilidade desta prática de manejo emergente no Brasil. / Globally, the population growth generates an increasing demand for energy, currently supplied by fossil sources. In this sense, public policies have stimulated the renewable energies sources, such as the production of second-generation ethanol (2G), from cellulosic materials, such as sugarcane straw. However, the straw removal can alter chemical, physical and biological soil properties and, finally, the crop yield. Therefore, the objective of this study was to evaluate the straw removal management effects on soil attributes and its impacts on the sugarcane growth and yield. The experiment was conducted near to Igaraçu do Tietê-SP. The soil was classified as an Oxisol \"Nitossolo Vermelho eutróferrico típico\". The experimental design used was a randomized blocks with five treatments and three replications. The evaluated treatments were the following amounts of straw deposited uniformly on the soil surface: 0; 2; 3.2 and 7.5 Mg ha-1 of dry matter mass. In addition, a treatment with 7.5 Mg ha-1 of straw piled within inter-row was tested. Soil chemical, physical and biological attributes such as pH, macronutrients, bulk density, soil resistance to penetration, carbon and nitrogen contents and stocks and microbial biomass were evaluated. For the majority of soil attributes, the evaluated soil layers were: 0-10; 10-20; 20-30 cm, however, the evaluated layers for the chemical attributes, at the end of the cycle, were: 0-5; 5-10; 10-20; 20-30 cm. In terms of plants, the number and height of plants were evaluated at 7, 15, 30, 45, 60, 90, 180 and 390 days after cutting (DAC). The leaf area index (LAI) was determined at 120, 150 and 180 DAC. The determination of the yield of the culture was performed by biometric analysis at 390 DAC. The plant-accumulation of nutrients was calculated for the treatments 0; 3.2; 7.5 Mg ha-1 at the end of the cycle. After one year of implementation of the experiment, the different amounts of straw did not change the chemical attributes, bulk density and soil C and N stocks. On the other hand, the maintenance of 7.5 Mg ha-1 of straw on soil surface reduced the soil compaction, especially within 150-cm spaced crop rows. The maintanance of larger amounts of straw had negative impacts on regrowth and initial tillering of sugarcane; however, with the course of the cycle, the plants recovered, with a similar stabilization in the number and height of the plant between the treatments, leading to similar values of LAI and stalk yield. In conclusion, for the conditions found in this study, short-term straw removal did not cause negative impacts on chemical, physical and biological attributes and, thus, a reduction in sugarcane yield. However, it is necessary to monitor the effects of the removal of sugarcane straw on soil and plant attributes over the medium and long term towards a better understanding of the sustainability of this emergent management practice in Brazilian sugarcane production.

Por apresentar elevada capacidade de produção e por ser uma das poucas cultivares adaptadas à produção de "chips", a cultivar de batata 'Atlantic' responde por cerca de 80% do mercado brasileiro formal de batata consumida desta forma. Com os objetivos de determinar as curvas de crescimento de massa de material seco, o acúmulo máximo e a exportação de nutrientes, em lavouras comerciais, em duas safras, pela cv. 'Atlantic', realizou-se este trabalho nos períodos de setembro a dezembro de 2001(safra das águas) e de fevereiro a março de 2002 (safra da seca) em Itapetininga-SP, localizada na latitude 23 o 35'08" S, longitude 48 o 02'50" W e com 636 m de altitude. Para isso, foram delimitadas quatro parcelas de 100 m X 17 m em lavouras comerciais, das quais foram realizadas coletas semanais das plantas a partir de 20 dias após o plantio. As plantas coletadas foram separadas em raízes, caules, folhas e tubérculos e secas e pesadas para a obtenção da massa de material seco nos diferentes estádios de desenvolvimento, sendo posteriormente moídas, e submetidas à análise para a obtenção da extração de nutrientes ao longo do ciclo. A análise estatística dos parâmetros avaliados foi feita considerando-se as épocas de plantio e quatro repetições. Os resultados permitiram as seguintes conclusões: a safra das águas produziu mais massa de material seco que a safra da seca. O acúmulo de massa da planta foi influenciado pelos estádios da cultura e pela safra: vegetativo (2,2 e 5,2%) < tuberização (13 e 20%) < enchimento de tubérculos (90 e 95%) < maturação (100 e 100%) para a safra das águas e da seca, respectivamente. A seqüência de acúmulo máximo na safra das águas foi: nitrogênio > potássio > cálcio > fósforo > magnésio > enxofre > ferro > manganês > zinco > boro > cobre. Na safra da seca, o potássio trocou de posição com o nitrogênio e o fósforo com o cálcio. O acúmulo máximo dos nutrientes depende da safra e do nutriente: nitrogênio (140 e 119); fósforo (17,6 e15,2); potássio (134 e 139); cálcio (21,7 e 14,6); magnésio (14,3 e 6,9); enxofre (10,8 e 14,6) em kg ha -1 ; boro (107 e 84,3); cobre (43,5 e 38,9); ferro (1.229 e 790); manganês (250 e 130); zinco (156,6 e 124,6) em g ha -1, para as safras das águas e da seca, respectivamente. A seqüência de exportação de nutrientes pelos tubérculos na safra das águas foi: nitrogênio > potássio > fósforo > enxofre > magnésio > cálcio > ferro > zinco > boro > manganês > cobre. Na safra da seca, potássio trocou de posição nitrogênio e cobre com manganês. / By presenting a high yield potencial and being one of the few cultivars adapted for chipping, Atlantic potatoes are responsible for approximately 80% of the brazilian formal potato chips market. With the objective of determining the growth curves, maximum nutrient accumulation and nutrient exportation, this study was carried out in Itapetininga, São Paulo State, at 23o 35'08" S of latitude, 48o 02'50" W of longitude and 636 meters above sea level, in two commercial areas of Atlantic potatoes from September to December 2001 (wet season), and from February to March 2002 (dry season). Four plots with 100 m X 17 m were set in each experiment and plants were collected weekly, after 20 days from planting. The collected plants were separated in roots, stems, leaves and tubers, dried and weighted, to obtain the dry-matter at different stages of growth. Samples were ground and analized to obtain nutrients concentration and to calculate nutrients accumulations. Statistical analysis considered the season and four replications. Results showed that wet season potatoes had higher dry-matter production than those of dry season. Nutrient accumulation was influenced by growth stage and season: vegetative (2.2 and 5.2%) < tuberization (13 and 20%) < tuber bulking (90 and 95%) < maturation (100 and 100%) for wet and dry season, respectively. The maximum nutrient accumulation in the wet season was: nitrogen > potassium > calcium > phosphorus > magnesium > sulphur > iron > manganese > zinc > boron > copper. During dry season, potassium changed position with nitrogen, and phosphorus with calcium. Maximum accumulation of nutrients (kg ha-1 for macronutrients and g ha-1 for micronutrients) depended on the season and on the nutrient: nitrogen (140 and 119); phosphorus (17.6 and 15.2); potassium (134 and 139); calcium (21.7 and 14.6); magnesium (14.3 and 6.9); sulphur (10.8 and 14.6); boron (107 and 84.3); copper (43.5 and 38.9); iron (1229 and 790); manganese (250 and 130); zinc (156.6 and 124.6), for wet and dry season, respectively. The nutrient exportation by the tubers in the wet season was: nitrogen > potassium > phosphorus > sulphur > magnesium > calcium > iron > zinc > boron > manganese > copper. In the dry season, potassium changed position with nitrogen, and copper with manganese.

Made available in DSpace on 2017-07-10T17:37:32Z (GMT). No. of bitstreams: 1 Sergio Luiz Marchi.pdf: 7672567 bytes, checksum: fdf541fa4a63c5627694d9c2bbd207f9 (MD5) Previous issue date: 2008-07-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The corn (Zea mays L.) is considered one of the main species used in the world, once that around 150.4 millions of hectares are cultivated per year, which contribute to the production of roughly 812.2 millions tons of grains. The reduction of the photosynthetic rate after the flowering can occur due to several factors as water stress, long foggy, destruction of the leaf area (plague and illnesses) and a high population of plants. This situation needs the usage of a store, mainly from the stem to filling the grains. In this context, the current work intended to evaluate the effect of the plants population, the levels of defoliation in agronomic aspects and the yield of the hybrid corn Pioneer 30F35. An experiment was conducted on a field of Palotina PR C.Vale Experimental Field in the agricultural year of 2006/2007. It was used the delineation in blocks, at random, using a factor scheme (4 x 5), with four replications. The factors evaluated were four plants population (45.000, 55.000, 65.000 and 75.000 plants ha-1) and five levels of defoliation (without defoliation 0%, 12.5%, 25%, 37.5% and 50% of defoliation) in full female flowering (notorious stigma-style). It was found to succeed that an interaction between the plants population and the rate of defoliation to the hybrid corn studied, to the biometric variables and the productive aspects studied happened. The rate of plants remobilization was not affected by the plants population change, although, the defoliation above 25% has negatively affected this variable. The rise of the plants population resulted in plants with less diameter of stem and a rise percentage of broken plants. This enlargement of the plants population and the level of defoliation resulted in a fall of the greater part of the production components and yield of the hybrid corn Pioneer 30F35 / O milho (Zea mays L.) é considerado uma das principais culturas utilizadas no mundo, visto que anualmente são cultivados cerca de 150,4 milhões de hectares, os quais contribuem para a produção de aproximadamente 812,2 milhões de toneladas de grãos. A redução da taxa fotossintética após o florescimento pode ser ocasionada por vários fatores como estresse hídrico, nebulosidade prolongada, destruição de área foliar (pragas e doenças) e alta população de plantas. Essa situação implica na necessidade de utilização das reservas da planta, principalmente do colmo para o enchimento de grãos. Neste contexto, o presente trabalho objetivou avaliar o efeito da população de plantas e níveis de desfolha em características agronômicas e produtividade do híbrido de milho Pioneer 30F35. O experimento foi conduzido no Campo Experimental da C.Vale em Palotina - PR no ano agrícola 2006/2007. Utilizou-se delineamento em blocos ao acaso em esquema fatorial (4x5), com quatro repetições. Os fatores avaliados foram quatro populações de plantas (45.000, 55.000, 65.000 e 75.000 plantas ha-1) e cinco níveis de desfolha (sem desfolha 0%, 12,5%, 25%, 37,5% e 50% de desfolha) no pleno florescimento feminino (estiloestigma visível). Verificou-se que não houve interação entre população de plantas e índice de desfolha, para o híbrido de milho estudado, para as variáveis biométricas e características produtivas estudadas. O índice de remobilização das plantas de milho não foi afetado pela variação da população de plantas, porém, a desfolha acima de 25% afetou negativamente esta variável. O aumento da população de plantas resultou em plantas com menor diâmetro de colmo e elevação na percentagem de plantas quebradas. O aumento da população plantas e do nível de desfolha resultou em queda na maioria dos componentes da produção e produtividade do híbrido de milho Pioneer 30F35

Made available in DSpace on 2017-07-10T17:37:50Z (GMT). No. of bitstreams: 1 Luiz Roberto_Faganello.pdf: 3165307 bytes, checksum: 227415100c749ddca305fcc14c6d386b (MD5) Previous issue date: 2012-03-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / It was developed a study on vegetative propagation on the rooting of Cordia trichotoma semi-woody in Summer and Fall of 2011. Therefore this study aimed to evaluate the effects of different concentrations of IBA (indolbutiric acetic) and NAA (naphthalene acetic) acids on the rooting and establishment of Cordia trichotoma semi-woody cuttings gathered from the sprout of Cordia trichotoma seedlings. To accomplish the objective of this study, two experiments were conducted. The first experiment considers the effect of different concentrations of IBA (Indolbutiric) and NAA (naphthalene acetic) acids on the rooting of Cordia trichotoma stem cutting gathered from the sprout of Cordia trichotoma seedlings produced by seeds, in February 2011, using micro sprinkler irrigation, eight times a day. Cordia trichotoma seedlings were produced by seeds constituting a miniclonal garden with subsequent pruning of the aerial part. Sprouts were harvested resulting in semi-woody cuttings with 12.0 cm long and 5.5 mm in diameter and a pair of leaves in the apical portion reduced in a half. The treatments consisted of fast immersion of the cuttings base in IBA and NAA acids in concentrations of 0, 2.000, 4.000, 6.000, 8.000 mg i.a. L-1 in a randomized block design with factorial arrangement 2 x 5. After 60 days of cutting, rooting percentage, roots number and length, sprouting percentage, the number of shoots and new leaves were evaluated as well as the survival and mortality. When there were differences, the averages were compared by F test at 5 % probability. For concentrations, it was used a polynomial regression analysis to 1 % by F test. The vegetal regulator IBA at a concentration of 8.000 mg L-1 showed higher cutting rootings. The cutting originated from seedlings produced by seeds must be better investigated as an alternative to the vegetative propagation of the species in Summer. The second experiment describes the effect of different concentrations of IBA (Indolbutiric acetic) and NAA (naphthalene acetic) acids on the rooting of stem cuttings gathered from the sprout of Cordia trichotoma seedlings in May 2011, produced by seeds using intermittent mist. Cordia trichotoma seedlings were produced by seeds constituting a miniclonal garden with subsequent pruning of the aerial part. Sprouts were harvested, from the pruning of the previous harvest, resulting in semi-woody cuttings with 12.0 cm long and 5.5 mm in diameter and a pair of leaves in the apical portion reduced in a half. The treatments consisted of fast immersion of the cuttings base in IBA and NAA acids in concentrations of 0, 2.000, 4.000, 6.000, 8.000 mg i.a. L-1 in a randomized block design with factorial arrangement 2 x 5. After 70 days of cutting, rooting percentage, roots number and length, sprouting percentage, the number of shoots and new leaves were evaluated as well as the survival and mortality. When there were differences, the averages were compared by F test at 5 % probability. For concentrations, it was used a polynomial regression analysis to 1 % by F test. The use of plant growth regulator IBA resulted in increased callus formation in cuttings. The cuttings originated from seedlings produced by seed must be further investigated as an alternative to vegetative propagation of the species for this time of year. / Desenvolveu-se um estudo para propagação vegetativa a partir de miniestacas de louro-pardo (Cordia trichotoma Vell. Arrabida ex Steudel) com a coleta dos propágulos no verão e outono de 2011. Assim o presente trabalho teve por objetivo avaliar os efeitos de diferentes concentrações do ácido indolbutírico (IBA) e do ácido naftalenoacético (NAA) no enraizamento e estabelecimento de miniestacas coletadas de brotações de mudas de louro-pardo. Para atender o objetivo deste trabalho, foram realizados dois experimentos. O primeiro experimento aborda o efeito de diferentes concentrações do IBA e NAA no enraizamento de miniestacas caulinares coletadas de brotações de mudas de louro-pardo produzidas por sementes, no mês de fevereiro de 2011, com o uso de irrigação por micro-aspersão, oito vezes ao dia. As mudas de louro-pardo foram produzidas através de sementes, selecionadas e constituindo um jardim miniclonal com posterior poda da parte aérea. As brotações foram colhidas resultando em miniestacas com 12,0 cm de comprimento, 5,5 mm de diâmetro e um par de folhas na porção apical reduzido pela metade. Os tratamentos compreenderam a imersão rápida da base das estacas em ácido indolbutírico e ácido naftalenoacético nas concentrações de 0, 2.000, 4.000, 6.000, 8.000 mg i.a. L-1 em delineamento de blocos casualizados com arranjo fatorial 2 x 5. Após 60 dias do estaqueamento foram avaliados a porcentagem de enraizamento, o número e comprimento das raízes, a porcentagem de brotações, o número de brotos e folhas novas, a porcentagem de estacas com calos, assim como a sobrevivência e mortalidade. Quando da existência de diferenças as médias foram comparadas pelo teste F a 5 % de probabilidade. Para concentrações, utilizou-se a análise de regressão polinomial a 1 % pelo teste F. O regulador vegetal IBA na concentração de 8.000 mg L-1 promoveu maior enraizamento de miniestacas. A estaquia oriunda de mudas produzidas por sementes deverá ser melhor investigada como alternativa para a propagação vegetativa da espécie com coleta de miniestacas no verão. O segundo experimento descreve o efeito de diferentes concentrações do IBA e NAA no enraizamento de miniestacas coletadas de brotações das mesmas mudas de louro-pardo, no mês de maio de 2011, com o uso de nebulização intermitente. As brotações foram colhidas, a partir da poda da coleta anterior, resultando em miniestacas com 12,0 cm de comprimento, e 5,5 mm de diâmetro e um par de folhas na porção apical reduzida pela metade. Os tratamentos compreenderam a imersão rápida da base das estacas em ácido indolbutírico (IBA) e ácido naftalenoacético (NAA) nas concentrações de 0, 2.000, 4.000, 6.000, 8.000 mg i.a. L-1 em delineamento de blocos casualizados com arranjo fatorial 2 x 5. Após 70 dias do estaqueamento foram avaliados a porcentagem de enraizamento, o número e comprimento das raízes, a porcentagem de brotações, o número de brotos e folhas novas, a porcentagem de estacas com calos, assim como a sobrevivência e mortalidade. Quando da existência de diferenças, as médias foram comparadas pelo teste F a 5 % de probabilidade. Para concentrações, utilizou-se a análise de regressão polinomial a 1 % pelo teste F. O emprego do regulador vegetal IBA resultou em maior calogênese média em miniestacas. A estaquia oriunda de mudas produzidas por sementes deverá ser melhor investigada como alternativa para a propagação vegetativa da espécie nesta época do ano.

Tecnologias que permitam explorar o potencial genético das variedades de cana-de-açúcar nos diversos ambientes de produção e possibilitem o planejamento da colheita são fundamentais para aumentar a rentabilidade do setor sucroenergético. Dentre estas tecnologias, o emprego de indutores de maturação destaca-se por possibilitar o manejo da cultura em seu sistema de produção e proporcionar melhorias na qualidade da matéria-prima. A utilização conjunta de maturadores e nutrientes em pré-colheita pode fornecer a indústria matéria prima de melhor qualidade tecnológica. Entretanto, questões relacionadas a épocas de utilização e a associação de maturadores com nutrientes não estão totalmente esclarecidas. Neste sentido, o propósito deste trabalho foi avaliar o efeito da aplicação de maturadores e nutrientes, em diferentes épocas de manejo, sobre parâmetros tecnológicos da cana-de-açúcar em início de safra. Foram conduzidos, em cana planta variedade RB 85 5453, dois experimentos compostos por 14 tratamentos: Controle, Orthosulfamuron, Etil-Trinexapac, Sulfometuron metil, Sulfometuron metil/ Boro 150 g/ha, Nitrato de Potássio, Boro 50 g/ha, Boro 150 g/ha, Boro 250 g/ha, Nitrato de Potássio + Boro 50 g/ha, Complexo de micronutrientes, Complexo de Micronutrientes + Biorregulador, Sulfometuron metil + Complexo de Micronutrientes, Sulfometuron metil + Complexo de Micronutrientes + Biorregulador; em delineamento de blocos casualizados, com 4 repetições. Foram realizadas 2 aplicações com intervalo de 33 dias entre aplicação. Os parâmetros Brix%, Fibra, Pol do caldo, Pol da cana), Pureza, Açúcares Redutores do Caldo, Açúcares Redutores da Cana e Açúcar Total Recuperável foram avaliados em intervalos quinzenais, aos 0, 15, 30, 45 e 60 dias após a aplicação dos produtos. Verificou-se que a utilização dos maturadores promoveu melhorias na qualidade da cana-de-açúcar e que a associação de nutrientes ao maturador não potencializou a ação dos maturadores. Diferentes épocas de aplicação dos produtos em pré-colheita resultaram em diferentes respostas da cana-de-açúcar. / Technologies to exploit the genetic potential of the varieties of sugarcane in different production environments and enable the planning of crop are essential to increase the profitability of the sugarcane industry. Among these technologies, the use of ripeners stands out by enabling the management of culture in its production system and provide improvements in the quality of the raw material. The joint use of ripeners and nutrients before the harvest can supply the raw material of better quality technology industry, however, issues related to the use of times and the ripeners of association with nutrients are not fully clarified. In this sense, the purpose of this study was to evaluate the effect of applying ripeners and nutrients at different times of management on technological parameters of sugarcane in early harvest. Were conducted, in sugarcane plant, variety RB 85 5453, two experiments consist of 14 treatments: Control, Orthosulfamuron, Ethyl-trinexapac, Sulfomethuron methyl, Sulfomethuron methyl + Boron 150 g/ha, Potassium Nitrate, Boron 50 g/ha, Boron 150 g/Ha, Boron 250 g/ha, Potassium Nitrate + Boro 50 g/ha, Complex micronutrients, Complex micronutrients + plant growth regulator, Sulfomethuron methyl + Complex micronutrients, Sulfomethuron methyl + Complex Micronutrients + Plant growth regulator; in a randomized block design with four replications. The applications were made on 28 March and 30 April. The parameters Brix%, fiber, Pol broth, Pol cane, Purity, reducing sugars, and recoverable total sugar were assessed at fortnightly intervals at 0, 15, 30, 45 and 60 days after application of the products. The use of ripeners promoted improvements in the quality of sugarcane and that the combination of nutrients to the ripeners didn\'t potentiate the action of ripeners. Different times of application of the products before the harvest resulted in different responses of sugarcane.

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Includes bibliographical refences

This project aims at investigating the effect of CO2 enrichment on the growth and gas exchange of C3, C3-C4 and C4 Panicum grasses. Potted plants were grown in soil under well watered conditions, in artificially lit environmentally controlled cabinets or naturally lit greenhouses at varying levels of CO2 enrichment. CO2 enrichment enhanced the dry weight of C3 and C4 Panicum species under optimal light and N supplies, but had no effect on the total leaf N or TNC concentrations. The high-CO2 induced photosynthetic reaction in the C3 species was accompanied by a reduced Rubisco concentration and was related to the conservation of the relative growth rate of the plant. Elevated CO2 had no effect on the photosynthetic capacity of the C4 species, but enhanced its CO2 assimilation rates under high light and N supplies. The effect of elevated CO2 on the leaf and stem anatomy reflected increased carbon supply at high CO2 in the C3 grass, and reduced transpiratory demand at high CO2 in C4 grasses. Consequently, it is clear that both C3 and C4 grasses are likely to be more productive under rising atmospheric CO2 concentrations. / Doctor of Philosophy (PhD)

One of the major water quality issues affecting waterways is eutrophication. Controlling the input of nutrients from municipal wastewater treatment plants (WTP’s) is a significant step in reducing eutrophication. Tertiary wastewater treatment for water quality improvement in particular Biological Nutrient Removal (BNR) is often expensive to construct with high maintenance costs. Constructed wetlands (CWs) offer an alternative wastewater treatment and have been used successfully worldwide to treat various types of wastewater. This study investigated the effectiveness of the Oxley Creek horizontal subsurface flow (SSF) CW for tertiary municipal wastewater treatment and the suitability of four native macrophyte species, Baumea articulata, Carex fascicularis, Philydrum lanuginosum and Schoenoplectus mucronatus. The investigation consisted of four main components: 1) Plants: monitoring plant establishment, growth, impact of cropping, gravel size, nutrient content and storage for the four macrophyte species trialed; 2) Water quality - effluent treatment: monitoring water quality and quantity entering and leaving the wetland to determine wastewater treatment; 3) Organic matter: accumulation of organic carbon within the wetland cells for the different gravel sizes (5mm and 20mm) and 4) Mass balance: combining nutrient storage by macrophytes with wastewater nutrient removal to determine proportion of nutrient removal by plant uptake. The Oxley horizontal SSF CW is situated at the Oxley Creek WTP in Brisbane (South- East), Queensland, Australia which has a sub-tropical climate. The experimental design involved four different substrate treatments: Cell A new 5mm gravel, Cells B and C old 20mm gravel and Cell D old 5mm gravel. Cells B, C and D had been operational since 1995 whereas Cell A had been in use since 2000. The wetland received secondary treated effluent direct from the Oxley Creek WTP at an average flow rate of 8L/min with a median hydraulic loading rate (HLR) of 0.12m/day and a hydraulic retention time (HRT) of 2 to 3 days. Each cell consisted of three gravel sections (Section 1 to 3) separated by 1m wide open water sections. Gravel Sections 2 and 3 were planted out with the four macrophyte species in October 2000, Section 1 remained unplanted. Plant health and leaf height was monitored to assess plant establishment and growth. Investigations into plant establishment and growth demonstrated that Carex was most suitable. Carex achieved the highest maximum leaf height and was not affected by pests and disease unlike Schoenoplectus and Philydrum. Above ground biomass was cropped in May and August 2001, with biomass of cropped material measured on both occasions. Plant health and re-growth following cropping of above ground biomass in May and August 2001 demonstrated that cropping retarded regrowth of Schoenoplectus and Philydrum. Carex and Baumea recovered quickest following cropping, with Carex achieving leaf height prior to cropping within 6 months. Proportion of biomass contained above and below ground was measured by collecting biomass samples three times over 9 months and dividing into plant components (roots, rhizomes, leaves, flowers and stems). Investigations into the proportion of above and below ground components indicated that >80% of biomass is contained above ground. Therefore cropping above ground biomass would potentially remove a significant proportion of nutrient storage from the CW. The results indicated that the ideal time for cropping was in spring/summer when plants are flowering particularly for Philydrum, whose flowering stems comprised 40% of total plant biomass. Flowering stems of Philydrum could potentially have a commercial use as a cut flower. Nutrient content of the four species in each cell was measured for individual plant components when first planted and after three (summer) and six (autumn) months growth. This was combined with biomass data to quantify nutrient bioaccumulation (nitrogen and phosphorus) by the four species in each cell. In terms of ability to bioaccumulate nitrogen and phosphorus, measurements of nutrient content and storage indicated that all four species were suitable. Nutrient storage was highest for Baumea and Carex. However high nutrient content may make the macrophytes more susceptible to pest and disease attack as found in this study for Philydrum and Schoenoplectus. Nutrient storage was highest in Cell A (new 5mm gravel) as a result of higher biomass achieved in this cell. The cropping and nutrient storage experiments indicated that Carex was the most suitable species for use in SSF CWs. Carex achieved the highest nutrient storage and had the fastest regrowth following cropping. Organic carbon accumulation between gravel particles measured as the proportion of material lost at 500oC was determined for gravel samples collected from each section for all four cells at 10cm depth increments (0-10cm, 10-20cm and 20-30cm). Investigations into organic carbon accumulation within the gravel substrate showed that organic accumulation was higher in the planted sections particularly for cells that had previously been planted with Phragmites australis. Organic accumulation was highest in the top 20cm of the gravel, which can be attributed to litter fall and root material. The effect of gravel size on plant growth, biomass, root depth and organic accumulation was assessed throughout the study. Investigations indicated that gravel size did not appear to affect biomass, maximum root penetration, re-growth following cropping and organic accumulation. Water quality from the inlet and outlet of each cell was measured fortnightly over 12 months (May 2001 to May 2002). Water quantity (HLR) was measured weekly using tipping buckets located at the inlet and outlet of each cell. Water quality and quantity were combined to investigate the nutrient removal efficiency of the wetland. The Oxley wetland was highly effective in reduction of TSS (<2mg/L) and COD (<30mg/L). Principal TSS and COD removal mechanism was physical with the first gravel section acting as a filter removing the majority of particulate material. Average loading rates to the wetland were 7.1 kg/ha/d PO4-P, 14 kg/ha/d NH4-N and 5.4 kg/ha/d NOx-N. Average daily mass removal rates ranged from 7.3 kg/ha NH4-N in Cell D to 4.6 kg/ha in Cell C (i.e. 37%-22% removal efficiency respectively); 5.2 kg/ha NOx-N in Cell C to 1.3 kg/ha in Cell A (i.e. 75%-22% removal efficiency) and 0.8 kg/ha PO4-P in Cell A to 0.1 kg/ha in Cell C (i.e. 10%-1% removal efficiency). Removal efficiency was calculated on a loads basis. Insufficient retention times (2-3 days based on tracer study) and anaerobic conditions (<1mg/L) limited further nitrogen removal. Negligible phosphorus removal for all cells was attributed to short retention time and likelihood of phosphorus adsorption being close to capacity. Investigation into the proportion of nutrient removal attributed to plant uptake demonstrated that nutrient uptake and storage in plant biomass accounted for <12% TN and <5% TP. This research project has provided several useful outcomes that can assist in future guidelines for designing effective SSF CWs in the subtropics/tropics. Outcomes include the importance of maintaining an adequate water level during the initial establishment phase. Maximising effluent treatment by pre-treatment of wastewater prior to entering SSF CWs to enable ammonia to be converted to nitrate and ensuring adequate hydraulic retention time. Carex fascicularis was the most suitable species particularly where harvesting regimes are employed. Philydrum flowering stems could be used as a cut flower in the florist trade.